On Cape Cod, they have lived like phantoms: ferocious fisher cats, flitting between the trees, feasting on small animals, and piercing the night with blood-curdling howls.
Common in Central and Western Massachusetts, the creatures have stalked around the Cape unseen. Some wildlife experts doubted they lived there at all. That is, until Tuesday morning, when Sandwich animal control officers found the first Cape-dwelling fisher cat in decades lying dead along Route 130, near the Massachusetts Military Reservation.
The fisher cat, cousin to the weasel and the wolverine, has slowly expanded its habitat, according to state wildlife experts, joining coyotes as forest-dwelling predators slowly repopulating on the Cape.
The animal found Tuesday was more than 3 feet long, weighed about 12 pounds, and was probably about a year old, according to Dick Turner, a wildlife biologist at the state Division of Fisheries and Wildlife office in Bourne.
It had been struck by a car and has been taken to MassWildlife biologists for analysis, Turner said.
''It's a good-sized one," he said. ''It's stirred up a lot of interest."
The long, slender animals, which have pointy teeth and long tails, eat mostly squirrels and other rodents. They occasionally attack housecats and small dogs, but they are not a threat to humans, Turner said.
Male fisher cats grow to about 3 feet and weigh between 8 and 16 pounds. Females are slightly shorter and weigh between 4 and 6 pounds. Their fur is typically rich brown or black, and their sharp claws help them scale trees. They are shy and are active at dawn and dusk, biologists said.
Extensive forest-clearing during the 1800s forced many of the animals from Massachusetts, said MassWildlife biologist Peter Mirick. They began to reappear in Central Massachusetts in the 1950s, he said, and have slowly migrated east.
Although fisher cats do not menace humans, the mystery surrounding them on the Cape has prompted dozens of calls to state and local animal control officials, each with wildly different and almost whimsical descriptions.
Several weeks ago, a Mashpee a woman reported hearing ''a horrible screech" coming from the wilderness near her home, Mashpee animal control officer June Daley said. The source, which the woman presumed was a fisher cat, was never found.
In Barnstable, a woman called animal control officers last spring when she saw what she described as a small otter harassing another animal, said Keith Williams, a Barnstable natural resources officer. The woman tried to shoo the animal away with a broom when, she told Williams, it lunged at her before scampering into the woods.
''The lady swore it was a fisher," he said. ''I guess it went after a possum and took out a squirrel."